Assessment of Nanosecond Laser Ablation Multi‐Collector Inductively Coupled Plasma‐Mass Spectrometry for Pb and Sr Isotopic Determination in Archaeological Glass: Mass Bias Correction Strategies and Results for Corning Glass Reference Materials

Abstract

This work presents an evaluation of various methods for in situ high‐precision Sr and Pb isotopic determination in archaeological glass (containing 100–500 μg g−1 target element) by nanosecond laser ablation multi‐collector‐inductively coupled plasma‐mass spectrometry (ns‐LA‐MC‐ICP‐MS). A set of four soda‐lime silicate glasses, Corning A–D, mimicking the composition of archaeological glass and produced by the Corning Museum of Glass (Corning, New York, USA), were investigated as candidates for matrix‐matched reference materials for use in the analysis of archaeological glass. Common geological reference materials with known isotopic compositions (USGS basalt glasses BHVO‐2G, GSE‐1G and NKT‐1G, soda‐lime silicate glass NIST SRM 610 and several archaeological glass samples with known Sr isotopic composition) were used to evaluate the ns‐LA‐MC‐ICP‐MS analytical procedures. When available, ns‐LA‐MC‐ICP‐MS results for the Corning glasses are reported. These were found to be in good agreement with results obtained via pneumatic nebulisation (pn) MC‐ICP‐MS after digestion of the glass matrix and target element isolation. The presence of potential spectral interference from doubly charged rare earth element (REE) ions affecting Sr isotopic determination was investigated by admixing Er and Yb aerosols by means of pneumatic nebulisation into the gas flow from the laser ablation system. It was shown that doubly charged REE ions affect the Sr isotope ratios, but that this could be circumvented by operating the instrument at higher mass resolution. Multiple strategies to correct for instrumental mass discrimination in ns‐LA‐MC‐ICP‐MS and the effects of relevant interferences were evaluated. Application of common glass reference materials with basaltic matrices for correction of ns‐LA‐MC‐ICP‐MS isotope data of archaeological glasses results in inaccurate Pb isotope ratios, rendering application of matrix‐matched reference materials indispensable. Correction for instrumental mass discrimination using the exponential law, with the application of Tl as an internal isotopic standard element introduced by pneumatic nebulisation and Corning D as bracketing isotopic calibrator, provided the most accurate results for Pb isotope ratio measurements in archaeological glass. Mass bias correction relying on the power law, combined with intra‐element internal correction, assuming a constant 88Sr/86Sr ratio, yielded the most accurate results for 87Sr/86Sr determination in archaeological glasses

Plant ash glass from first century CE Dibba, U.A.E

“…The plasma was operated under wet conditions by pumping 100 μl/min 3% HNO 3 solution to improve stability. Corning D was used as a secondary standard for this analysis; its isotopic composition and suitability as standard are discussed elsewhere (Van Ham-Meert et al 2018). Instrumental settings are found in Table 3.…”

Nanosecond Laser Ablation–Multicollector Inductively Coupled Plasma-Mass Spectrometry for in Situ Fe Isotopic Analysis of Micrometeorites: Application to Micrometer-Sized Glassy Cosmic Spherules

“…Some authors have reported that the isotope ratio drift encountered in the case of short transient signals can be corrected for by taking into account the differences in response times between Faraday cups or between a Faraday cup and an ion counter or by correcting the values for the slow response of the Faraday preamplifier . Therefore, strategies to correct for instrumental mass discrimination in LA–MC-ICP-MS and the effects of relevant interferences need to be evaluated . Although nanosecond-based LA systems are more susceptible to matrix effects and isotope fractionation than femtosecond-lasers, improvements in the instrumentation and correction strategies developed in recent years were able to mitigate these effects and to generate accurate and sufficiently precise isotope ratio results in some contexts. , Moreover, nanosecond-based LA systems are easier to operate and are more affordable, as a result of which they are considerably more widespread.…”

“…19 Therefore, strategies to correct for instrumental mass discrimination in LA−MC-ICP-MS and the effects of relevant interferences need to be evaluated. 20 Although nanosecond-based LA systems are more susceptible to matrix effects and isotope fractionation than femtosecond-lasers, 21 improvements in the instrumentation and correction strategies developed in recent years were able to mitigate these effects and to generate accurate and sufficiently precise isotope ratio results in some contexts. 20,22 Moreover, nanosecond-based LA systems are easier to operate and are more affordable, as a result of which they are considerably more widespread.…”

Provenancing of cement using elemental analyses and isotope techniques – the state-of-the-art and future perspectives

“…Another technique worth mentioning is laser ablation (LA) ICP-MS. Van Ham-Meert and co-authors 124 published an article about LA-ICP-MS for Pb and Sr isotopic determination in archaeological glass. This technique was also used for provenancing of ceramics, 98,99 as well as for cultural heritage research.…”